1. Field of the Invention
The present invention relates to a mixer for a capsule for dental restoration material, which is used for mixing a powder component and a liquid component in a capsule for dental restoration material accommodating therein two components of definite amount of the powder component and the liquid component as previously weighed separately, each constituting a dental restoration material to be used in filling, cementing, lining and other applications for restoration of a tooth in the dental remedy field, by rendering a mixing compartment in vacuo so that the mixture may not substantially contain air bubbles therein.
2. Description of the Related Art
In general, a dental restoration material is used for restoration of a tooth, such as filling, cementing and lining. As the dental restoration material, a two-component system material comprising a powder component and a liquid component, which are reacted with each other upon mixing, is usually used. Hitherto, this two-component system dental restoration material was provided for use after appropriately weighing the powder component and the liquid component and mixing them with each other. However, in recent years, for the purposes of omitting a weighing operation of the powder component and the liquid component and an operation for accommodating the dental restoration material after mixing in a syringe for administering it to a site to be restored, there have been developed capsules for dental restoration material, in which definite amounts of the powder component and the liquid component are previously weighed and accommodated separately from each other, the isolated state is released at a desired time, the both components are mixed with each other by mechanical shaking in a mixer, and the resulting mixture is extruded and administered directly to a site to be restored, such as a tooth cavity, through a nozzle.
For example, in a capsule as disclosed in Japanese Patent Publication No. 38853/1991, a powder component of the two components is accommodated in a mixing compartment of a capsule main body, and the other liquid component is charged in a bag (pillow) formed by a sheet film, which is mounted on a side portion of the mixing compartment accommodating the powder component by means of a clip. The capsule main body has an outlet hole in a front end portion thereof. This outlet hole can be clogged in a cylindrical bearing portion in a rear end portion of a nozzle. Further, the nozzle is kept from the outside by means of a separately formed cap, thereby preventing the powder component from leakage out of the mixing compartment. And, when in use, the clip is pushed toward direction of the mixing compartment, thereby smashing and breaking the pillow accommodating the liquid component therein; the liquid component is made to flow into an interior of the mixing compartment through an aperture provided on a side wall of the mixing compartment, followed by shaking in a mixer to mix the liquid component and the powder component with each other; the cylindrical bearing portion in the rear end portion of the nozzle is then rotated to release a passage of the nozzle; and a plunger is pushed by means of a push rod of a separately prepared applier to extrude the mixture through the nozzle.
Further, a two-component system capsule for mixing and discharging as disclosed in Japanese Patent Laid-Open No. 268555/1987 has a bag (pillow) in which a powder component of two components is accommodated in a mixing compartment within a capsule main body, and the other liquid component is accommodated in a bag (pillow) formed by a sheet film comprising a resin, a metal foil, or a laminate comprising a resin and a metal foil. In this pillow, the strength in the main body side is previously set to be low, and the pillow is attached by a cap to be screwed on the container main body in the front end side of the container main body. In use, when the cap is firmly screwed on the capsule main body and moved, the pillow is ruptured, the sheet in the capsule main body side is broken, and the liquid component flows into the mixing compartment through an outlet hole provided on a center axis of the front end of the capsule main body. Thus, when shaking is performed in a mixer, the liquid component is mixed with the powder component. After mixing, a through rod set within a nozzle provided on a center axis of the cap is pushed in and breaks through the sheet of the pillow on the cap side, i.e., on the nozzle side, to form a discharge outlet for the mixture. Thereafter, the through rod is removed, a plunger set in the interior of the rear end portion of the capsule main body is moved towards the side of the front end portion of the capsule main body by a push rod of an applier, and the mixture in the mixing compartment is discharged through the nozzle.
Further, like Japanese Patent Laid-Open No. 268555/1987 as cited above, Japanese Patent Publication No. 81384/1991 discloses a capsule for dental restoration material in which a bag (pillow) having a liquid component accommodated therein, which is formed by a sheet film such as an aluminum foil, is provided on the outside of a front end of a mixing compartment of a capsule main body; and the pillow is ruptured by screwing and pressing a cap, thereby making the liquid component flow into the mixing compartment through an outlet hole on a center axis of the capsule main body. Thus, when a mixer is shaken, the liquid component is mixed with the powder component. Thereafter, a pillow breakthrough body-equipped plunger provided in a rear end portion of the capsule main body is moved by means of a push rod of an applier, to break through a front end of the pillow on the nozzle side, thereby extruding the mixture in the mixing compartment.
Each of the above-described capsules used a pillow in which the liquid component is wrapped by a sheet film using a metal foil or the like. Thus, as a capsule not using such a pillow, Japanese Patent Laid-Open No. 131459/1996 proposes a capsule having a structure comprising a cylindrical capsule main body having a mixing compartment for accommodating a powder component therein, in which a thin film-like seal portion for clogging a circular outlet hole for mixture, which is provided on a center axis of a front end portion, is formed, male screw is provided on an outer periphery side surface from the front end portion to a center portion, and an applier-engaging groove is formed on an outer periphery side surface in the vicinity of a rear end portion; a cup-like liquid-accommodating tool for accommodating a liquid component therein, in which a thin film-like seal portion forming a circular flow-in hole for the liquid component is formed on a center axis of a front end portion thereof, an evagination portion that is embedded in a cylindrical portion for forming the mixing compartment of the capsule main body is provided on an outer periphery surface in the vicinity of the front end portion, and a convex stopper having a size such that it does not easily slide into the capsule main body during breaking through the thin film-like seal portion to form the flow-in hole for the liquid component, however, when a large force is applied, it the stopper not inhibited to slide into the capsule main body, is provided on an outer side surface in the vicinity of a rear end portion thereof; a plunger, in which a tip portion thereof for breaking through the thin film-like seal portion of the liquid-accommodating tool and the thin film-like seal portion of the capsule main body has a planar rod-like protrusion in its front end portion, and an evagination portion that is engaged with a cylindrical portion within the liquid-accommodating tool is provided on an outer periphery surface in the vicinity of the front end portion; a cap having a nozzle-engaging mouth on a center axis of a front end portion thereof and screw provided, on an inner periphery side surface thereof with a female screw to be screw engaged with the male screw that is a screw provided on the capsule main body; and a nozzle having a shape such that a rear end portion thereof can be engaged with the outer surface of the front end portion of the capsule main body.
In the capsules having such various structures, when the dental restoration material comprising two components of definite amounts of the previously weighed powder component and liquid component as is mixed by shaking in a mixer, air present in the mixing compartment mingles into the mixture to stay therein. For this reason, the dental restoration material administered in a restoration site such as a cavity of a tooth contains the air bubbles. Accordingly, the capsules of the related art involved various problems including reduction in the strength and a change in the color tone with respect to the dental restoration material.
Thus, in order to overcome the above problems of the capsules for dental restoration material of the related art and to provide a capsule for dental restoration material, which is free from the occurrence of a phenomenon wherein, when a dental restoration material of the related art comprising two components of definite amounts of previously weighed powder component and liquid component accommodated in a capsule for dental restoration material is mixed, air present in a mixing compartment mingles as air bubbles into the mixture, we, the present inventors proposed in Japanese Patent Application No. 2000-163408 a capsule for dental restoration material having an air-permeable filter that does not allow to pass the powder component and the liquid component therethrough but can ventilate air within the mixing compartment outside of the mixing compartment placed at least in a part of a peripheral wall of the mixing compartment.
An object of the present invention is to provide a mixer for a capsule for dental restoration material, in which air present in the compartment for mixing the dental restoration material comprising two components of the powder component and the liquid component accommodated in the capsule for dental restoration material as proposed above by the inventors is sucked out of the mixing compartment to render the mixing compartment in vacuo, whereby the powder component and the liquid component can be mixed with each other by shaking.
In order to achieve the above-described object, the present inventors made extensive and intensive investigations. As a result, it has been found that the object can be achieved by a mixer for a capsule for dental restoration material for mixing a powder component and a liquid component of a dental restoration material by shaking within a mixing compartment of a capsule for dental restoration material having an air-permeable filter which can ventilate air within the mixing compartment into the outside of the mixing compartment, the filter constituting as an outer wall at least a part of a peripheral wall of the mixing compartment, wherein the mixer is provided with a capsule holding chamber for holding the capsule for dental restoration material in a portion other than a portion corresponding to the air-permeable filter, and the capsule holding chamber is connected to a vacuum device, leading to accomplishment of the present invention.
Further, it has also been found that when, in the mixer for a capsule for dental restoration material, the vacuum device is an ejector to be connected to a compressed air supply device for a dental unit, a compressed air supply device for a dental unit placed in a dental clinic can be used as a power source thereof, and hence, the system can be made at low cost and of simple structure.